In the field of magnetic resonance imaging, it is known to employ an air ventilation system having a fan for cooling the patient or other parts of a scanner unit of a magnetic resonance imaging system. A cooling system for circulating a coolant such as air to cool a cylindrical patient bore of a magnetic resonance imaging system is described, for example, in US patent application 2005/0030028 A1. The US patent application US 2009/0134875 discloses a cooling unit for a magnetic resonance imaging system with a duct and a fan to circulate cooling air of the circuit elements of an RF coil. The fan is provided outside the shield room to avoid the electric system of the fan to influence signals received by the RF coil.
From efficiency considerations it is preferable to place the fan inside a radio frequency shielded room that the scanner unit is customarily installed in. In such a constellation, measures have to be taken to avoid electromagnetic interference (EMI) between the fan in operation and the EMI-susceptible electronics of the scanner unit, for instance by installing a radio frequency shield around the fan.